Synthesis and characterization of bis nitrato[4-hydroxyacetophenonesemicarbazone) nickel(II) complex as ionophore for thiocyanate-selective electrode

The PVC based-ion selective electrode viz., bis nitrato[4-hydroxyacetophenone semicarbazone] nickel(II) as an ionophore was prepared for the determination of thiocyanate ion. The ionophore was characterized by FT-IR, UV-vis, XRD, magnetic moment and elemental analysis (CHN). On the basis of spectral studies an octahedral geometry has been assigned. The best performance was obtained with a membrane composition of 31% PVC, 63% 2-nitrophenyl octylether, 4.0% ionophore and 2.0% trioctylmethyl ammonium chloride. The electrode exhibited an excellent Nernstian response to SCN- ion ranging from 1.0 x 10(-7) to 1.0 x 10(-1) M with a detection limit of 8.6 x 10(-8) M and a slope of -59.4 +/- 0.2 mV/decade over a wide pH range (1.8-10.7) with a fast response time (6 s) at 25 degrees C. The proposed electrode showed high selectivity for thiocyanate ion over a number of common inorganic and organic anions. It was successfully applied to direct determination of thiocyanate in biological (urine and saliva) samples in order to distinguish between smokers and non-smokers, environmental samples and as an indicator electrode for titration of thiocyanate ions with AgNO3 solution. (C) 2016 Elsevier B.V. All rights reserved.